Method for selecting pile area under deep sea exploration platform

Abstract

Deep sea exploration platform pile area selection method, the existing seabed topography detection method needs to carry out large-scale online topography reconstruction on the seabed topography of the pile area, and there are problems of large amount of calculation and poor real-time performance, which belongs to the field of seabed topography detection. The present application comprises: extracting the DEM gradient and variance of the seabed topography, and generating a point cloud map of the seabed topography; scanning the selected pile area in the point cloud map to obtain the average gradient and variance D(x,y) of the selected pile area; selecting the point with the minimum value of the average gradient and variance of each selected pile area in the visible area of the pile field, respectively, and each selected pile area is centered on the selected point, and the neighborhood of the center is divided into gradient selected pile area and variance selected pile area i=1,2,...,N d , N d is the preset number of selected pile areas. It can be applied to other fields such as lunar exploration.

Description

Technical Field

[0001] This invention relates to a method for selecting the pile-laying area of ​​a deep-sea exploration platform, belonging to the field of seabed topography and geomorphology exploration. Background Technology

[0002] The 21st century is known as the "century of the ocean," and seabed science is a crucial field in marine scientific research. During seabed resource exploration, information on seabed topography and geomorphology serves as the foundation for seabed resource surveying and scientific research, and is of significant value for the safe deployment of deep-sea exploration platforms and operational safety. Currently, seabed topography and geomorphology detection mainly includes seabed acoustic detection, marine gravity and magnetic measurements, and seabed optical (including laser) detection. One method utilizes underwater laser line scanning experimental devices to perform laser stripe extraction, feature extraction and matching, and other processing on images obtained by the laser line scanning device before performing 3D reconstruction. The results show that the calibrated laser line scanning imaging device can achieve fast and accurate imaging. Another method proposes an automatic identification method for complex seabed topography areas for nautical chart generalization, demonstrating its ability to identify such areas. However, both methods require large-scale reconstruction of the seabed topography for feature extraction, and the system suffers from scale uncertainty. Furthermore, seabed topography feature extraction is based on multibeam backscatter intensity extraction of angle response (AR) features and backscatter image features. Experimental results show that multibeam systems have good performance in seabed topography detection. Building upon this, a combination of a POS MV system and a multibeam echo sounder system has been employed for navigation, positioning, and seabed surveying, achieving good measurement results for seabed topography in high-latitude polar regions. Furthermore, methods for retrieving seabed topography from gravity data have been investigated, and experimental results verify that the proposed methods can effectively acquire high-precision seabed topography. However, all of these methods require large-scale online topography reconstruction of the seabed in the staking area, resulting in high computational costs and poor real-time performance. Summary of the Invention

[0003] To address the issues of large computational load and poor real-time performance in existing seabed topography and geomorphology detection methods that require large-scale online reconstruction of the seabed topography in the pile-laying area, this invention provides a method for selecting the pile-laying area of ​​a deep-sea exploration platform.

[0004] The present invention provides a method for selecting a pile-laying zone for a deep-sea exploration platform, comprising:

[0005] Extract the DEM gradient and variance of the seabed topography to generate a point cloud map of the seabed topography.

[0006] Scan the candidate pile-laying area in the point cloud map to obtain the average gradient of the candidate pile-laying area. The average gradient and variance D(x,y) of each candidate pile-laying zone are selected as the points with the smallest values ​​within the visible area of ​​the pile-laying field. and Each candidate pile-laying zone is defined by taking the selected point as the center and delineating the neighborhood of that center as the gradient candidate pile-laying zone. and variance candidate pile area N d This represents the preset number of candidate pile driving areas.

[0007] As a preferred option, the gradient candidate pile area Variance candidate pile area

[0008] in, Indicated by The σ-neighborhood centered on the center Gradient selection range in pixel coordinate system of the pile area The range of variance values ​​in the pixel coordinate system of the candidate pile area

[0009] As a preferred option

[0010] Represents the visible region, x, y = 1, 2, ..., N pix N pix This indicates the number of pixels in the x and y directions.

[0011] As a preferred option, the DEM gradient is:

[0012]

[0013]

[0014] Where (x,y) represents the horizontal coordinates of the midpoint of the seabed topography, H(x,y) represents the gradient value, and θ(x,y) represents the gradient direction. x (x,y) represents the gradient in the x-direction, H y (x,y) represents the gradient in the y-direction.

[0015] As a preferred option

[0016]

[0017]

[0018] Among them, S x (i,j) and S y (i,j) represent the Sobel operator S in the x-direction. x Sobel operator S in the y-direction y In the i-th row and j-th column, T(x,y) represents the elevation image;

[0019] Sobel operator in the x direction

[0020] Sobel operator in the y-direction

[0021] As a preferred option, the variance D(x,y) is:

[0022]

[0023] The beneficial effects of this invention are that it proposes a DEM-based strategy for selecting target areas, using gradient and variance to select candidate target areas. This technique can also be applied to other fields such as lunar exploration. Compared to the aforementioned methods, the method proposed in this invention considers extracting terrain features at a small scale, avoiding large-scale online terrain reconstruction of the seabed topography in the target area, thus improving real-time performance and security. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the principle of the present invention;

[0025] Figure 2 This is the original DEM elevation map;

[0026] Figure 3 The variance is the candidate for the next pile area;

[0027] Figure 4 The variance represents the topographic relief of candidate pile areas A and B;

[0028] Figure 5 Variance of the terrain undulation in the candidate pile area;

[0029] Figure 6 The gradient is the candidate area for pile driving;

[0030] Figure 7 The terrain undulations of candidate pile-laying areas A and B are shown;

[0031] Figure 8 This represents the terrain undulation of the candidate pile area. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0035] To study the selection of anchoring areas for deep-sea exploration platforms operating at sea, this implementation method considers the need for real-time data collection on topographic elevation and small-scale topographic roughness. It utilizes gradient and variance-based seabed topographic feature extraction techniques from a Digital Elevation Model (DEM) to perform fuzzy processing and reconstruction of the seabed topography, generating a point cloud map. Research shows that the point cloud map information can reflect the topographic roughness of the area and, to some extent, the slope information. This method can provide a rough assessment of the topographic features of the anchoring area, identifying potential anchoring areas for deep-sea exploration platforms.

[0036] The method for selecting the pile-laying area for the deep-sea exploration platform in this embodiment includes:

[0037] Step 1: Extract the DEM gradient and variance of the seabed topography to generate a DEM point cloud map of the seabed topography:

[0038] A DEM can be represented as a function T(x,y) of coordinates (x,y) on a horizontal plane, representing the height of each point relative to a reference plane. The horizontal coordinates (x,y) in an elevation image T(x,y) are typically in pixels, satisfying x,y = 1, 2, ..., N. pix , where N pix The number of pixels in the x and y directions. The gradient of the DEM characterizes the relative elevation relationship between each point and its surrounding neighbors, and can be used to assess whether the terrain near each point is flat;

[0039] This implementation uses the Sobel operator to calculate the DEM gradient. The Sobel operator is as follows:

[0040]

[0041] In equation (1), S x S y These are the gradient operators in the x and y directions, respectively. Let S... x S y By convolving the elevation images T(x,y) with the elevation images respectively, we can obtain the gradients H in the x and y directions. x and H y :

[0042]

[0043] Among them, S x (i,j) and S y (i,j) is the Sobel operator S x S y The element in row i and column j.

[0044] Therefore, the gradient values ​​and gradient directions at each point in the image are:

[0045]

[0046] The elevation variance of a DEM is the average of the squared differences between the elevation values ​​of all pixels within a local area of ​​the DEM and the average elevation value of that area. It reflects the roughness of the terrain in that area. Variance and gradient are important indicators in terrain analysis, providing a rough assessment of seabed topographic features to identify potential staking areas.

[0047] Step 2: Scan the candidate pile-laying area in the DEM point cloud map to obtain the average gradient of the candidate pile-laying area. The variance D(x,y);

[0048] To further reflect the overall condition of the underscore area, for a pixel region of size (2σ+1)×(2σ+1) on the DEM, where σ is half the window length on the map, an L×L scanning window is used to calculate the mean gradient within the window.

[0049]

[0050] To calculate the elevation variance D(x,y) of the DEM in a certain point area, a sliding window of size L×L is selected to scan the candidate pile area. The pixel area of ​​(2σ+1)×(2σ+1) is still selected, and then the elevation variance of the DEM in the sliding window is calculated in turn.

[0051]

[0052] In the formula, T 2 (x,y) is the square of each element in T(x,y).

[0053] Step 3: Initialize the value range of the center of the candidate pile area in the pixel coordinate system:

[0054] Calculate the average gradient magnitude of the DEM After obtaining the variance D(x,y), the gradient and variance candidate piling regions can be extracted. The visible area of ​​the entire piling field, after edge removal, can be denoted as the range of values ​​in the pixel coordinate system as follows:

[0055]

[0056] Step 4: Select the points where the average gradient and variance of the candidate pile-laying area i are minimized within the visible region of the pile-laying field, respectively. and

[0057] The initial value of i is 1. When i = 1, by... and Selected from Points with smaller values ​​than D(x,y) can be selected as potential pile-laying areas. That is, selecting... The point in D(x,y) that has the smallest value:

[0058]

[0059] When i takes other values, the values ​​are selected again from the range of values ​​in the pixel coordinate system of the candidate pile area based on the gradient and variance obtained in the previous iteration. The point in D(x,y) that has the smallest value:

[0060] Step 5: In the candidate pile area i, select the points respectively. and Centered on the boundary, the neighborhood of this center is defined as the gradient candidate pile-down zone. and variance candidate pile area Proceed to step 4 until i = N d N d This represents the preset number of candidate pile driving areas.

[0061]

[0062] In addition, to avoid the new point obtained by using equation (8) being at the minimum point and The nearby, and consequently the designated candidate pile-laying area, is also related to... Overlapping problem. Definition:

[0063]

[0064] Repeat steps 3 through 5 to select a series of gradient candidate pile-laying points. and variance of the candidate pile-down area points Where i = 1, 2, ..., N d .

[0065] Simulation parameter settings for the selected pile driving area:

[0066] The seabed topography was blurred to generate a high-precision point cloud map. The generated DEM map has a field of view of 2km × 2km and a resolution of 0.01m. The image parameters and simulation platform parameters for simulation analysis are shown in Table 1.

[0067] Table 1 Simulation Condition Settings

[0068]

[0069] Simulation analysis of the candidate pile driving area:

[0070] Original DEM elevation map as follows Figure 2 As shown in the map, the bright areas correspond to highlands in the DEM, and the dark areas correspond to lowlands. The elevation variation of the terrain selected in this embodiment is approximately ±10m.

[0071] Select the variance candidate pile area in the DEM elevation map;

[0072] Schematic diagram of the invention Figure 3 The image shows eight candidate pile areas selected based on the selected variance.

[0073] Figure 4 The data shows the topographic undulations of candidate piling areas A and B. In area A, the topographic drop (TD) refers to the vertical distance from the highest point to the lowest point, which is 0.68m with a variance of 0.1868, indicating relatively flat terrain. In area B, the topographic drop is 0.77m with a variance of 0.1926, also indicating relatively flat terrain.

[0074] Schematic diagram of the invention Figure 5 The topographic relief of the remaining 6 variance candidate pile areas is shown.

[0075] As can be seen, the eight candidate pile-laying areas are relatively flat areas on the original DEM elevation map. Table 2 shows the detailed information of these eight areas, which shows that the maximum terrain elevation difference in these eight areas is 1.14m, which is much lower than the overall elevation undulation of the pile-laying site.

[0076] Table 2 Variance Information for Candidate Pile-Down Zones

[0077] A 0.68 0.1988 0.1868 B 0.77 0.2896 0.1926 C 0.87 0.3124 0.2464 D 1.14 0.2309 0.2019 E 1.00 0.1738 0.3694 F 0.77 0.2465 0.3628 G 0.87 0.1679 0.4014 H 0.92 0.2851 0.3216

[0078] The average gradient of each pile-laying area can be calculated from the DEM map, and areas with smaller gradients are selected as potential pile-laying areas. Figure 6 The image shows eight candidate pile driving zones selected based on the chosen gradient.

[0079] Figure 7 The terrain undulations of the candidate gradient pile areas A and B are shown. Area A has a terrain drop of 0.98m and an average gradient of 0.1739m / pix, and the terrain is relatively flat. Area B has a terrain drop of 1.02m and an average gradient of 0.074m / pix, and the terrain in this area is also relatively flat.

[0080] Figure 8The table shows the terrain undulations of the remaining candidate gradient areas. Table 3 presents detailed information for these eight areas. It can be seen that the terrain elevation difference in these eight areas does not exceed 1.24m, indicating that the terrain in these areas is relatively flat.

[0081] Table 3 Information on candidate pile driving zones with gradients

[0082] A 0.98 0.1739 0.5660 B 1.02 0.2074 0.3342 C 0.87 0.1846 0.2273 D 0.79 0.2309 0.8939 E 0.74 0.1803 0.4318 F 1.24 0.2034 0.5647 G 0.91 0.1976 0.4168 H 1.14 0.2089 0.5403

[0083] in conclusion

[0084] This implementation proposes an algorithm for extracting candidate seabed pile-laying areas for deep-sea exploration platforms based on a DEM (Digital Elevation Map). Using the calculated gradient and variance information from the DEM elevation map, candidate pile-laying areas based on gradient and variance are obtained. Experimental results show that the obtained candidate pile-laying areas are indeed relatively flat regions in the original DEM elevation map. Further analysis of the experimental results for the gradient candidate pile-laying areas confirms that the terrain in this area is indeed relatively flat. In summary, the method proposed in this implementation has advantages such as low computational cost, high real-time performance, and fast selection speed, which can ensure the safety of pile-laying operations on deep-sea exploration platforms.

[0085] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A method for selecting the pile driving area for a deep-sea exploration platform, characterized in that, The method includes: Extract the DEM gradient and variance of the seabed topography to generate a point cloud map of the seabed topography. Scan the candidate pile-laying area in the point cloud map to obtain the average gradient of the candidate pile-laying area. and variance ; The points where the average gradient and variance of each candidate pile-laying zone are minimized within the visible area of ​​the pile-laying field are selected as follows: and For each candidate pile-laying zone, the neighborhood of the selected point is defined as the gradient candidate pile-laying zone. and variance candidate pile area , , The number of candidate pile driving areas is preset; Gradient candidate pile area Variance of the candidate pile area ; in, Indicated by Centered Neighborhood, The range of pixel coordinates in the gradient candidate pile area , The range of variance values ​​in the pixel coordinate system of the candidate pile area ; ； Indicates the visible area. , express Number of pixels in the direction.

2. The method for selecting the pile-laying area of ​​a deep-sea exploration platform according to claim 1, characterized in that, The DEM gradient is: ； ； in, Represents the horizontal coordinates of the midpoint of the seabed topography. Represents the gradient value. Indicates the gradient direction. express Gradient of direction, express Gradient of direction.

3. The method for selecting the pile driving area for a deep-sea exploration platform according to claim 2, characterized in that, ； ； in, and They are respectively Directional Sobel operator , Directional Sobel operator The OK List, Represents an elevation image; Directional Sobel operator ; Directional Sobel operator .

4. The method for selecting the pile-laying area of ​​a deep-sea exploration platform according to claim 1, characterized in that, variance for: ； 。 5. A computer-readable storage device storing a computer program, characterized in that, When the computer program is executed, it implements the method for selecting the pile area of ​​the deep-sea exploration platform as described in any one of claims 1 to 4.

6. A device for selecting a pile driving area for a deep-sea exploration platform, comprising a storage device, a processor, and a computer program stored in the storage device and executable on the processor, characterized in that, The processor executes the computer program to implement the deep-sea exploration platform pile area selection method as described in any one of claims 1 to 4.

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